Hey, sorry about that. You need to pick up a plate from the plate stack by pressing E and bring it to one of the preparation mats at the front of the kitchen. From there you can place items on those. The game also features a 1-item inventory mechanic so if you pick up an item before putting a plate out, you'll need to discard the item (in the trash) to be able to hold the plate. I'm glad you were able to enjoy the game regardless.